Oct. 24 (UPI) -- New research suggests millions of miles of planned roads shouldn't be built, as many projects will sacrifice valuable environmental and ecological resources for limited benefits.
The majority of planned new roads are slated to be paved through high-rainfall tropical and subtropical areas, mainly in developing countries. The areas are often rich in biodiversity and home to vulnerable species.
"In these high-rainfall regions, even expensive roads can be rapidly rendered useless by numerous pot-holes, road slumping, and landslides," Mohammed Alamgir, a researcher at James Cook University in Australia, said in a news release. "Unless there's expensive ongoing maintenance, big road projects can easily become giant money-losers for developing nations."
Corruption is one of the reasons ill-advised road plans are approved. Government officials regularly give the go-ahead after they're bribed by those who will directly profit from the road's construction.
"Often contractors build substandard roads -- for example, using too little cement or road base -- and then pocket the stolen proceeds, leaving the roads even more vulnerable to rapid collapse," said James Cook University professor William Laurance.
In a paper published this week in the journal Current Biology, Alamgir, Laurance and their colleagues detailed the economic, social and environmental costs and benefits of road building projects across the globe. Their findings suggest, in most cases, the costs significantly outweighs the benefits.
Previous research has a shown new roads lead to increases in illegal logging and poaching in developing countries rich in valuable natural resources. Land for road construction is regularly commandeered from indigenous groups and other marginalized communities, with infrastructure projects often serving as flash points for social conflict.
"We knew roads were very dangerous for the environment," said researcher Mason Campbell. "But to us the big surprise was just how risky they were from economic and social perspectives."
More than 32,000 miles of new roads are currently planned for Africa, and Asia's developing countries are expected to double the number of paved roads in the region over the next three years. Almost all of these projects need to be more carefully considered, and many should not be built, researchers argue.
"It's a very dangerous time," said Laurance. "Our exhaustive study suggests that the economic, social and environmental risks of poorly planned roads are much greater than is generally understood."